Capacitor Electrode Stabilization via Segmented Etching
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Solution Overview
Problem
The increasing density of integrated circuits poses a challenge in maintaining high storage capacitance with decreasing capacitor area, as capacitor electrodes formed in deep openings are prone to toppling during etching and processing due to their tall and narrow structure, which complicates the exposure of outer sidewall surfaces for increased capacitance.
Innovation Solution
A method involving the formation of support material over a substrate, where a first capacitor electrode is formed within openings, and subsequent etching using liquid and dry etching fluids to expose and remove support material, allowing for the formation of a capacitor dielectric and a second electrode, thereby stabilizing the electrodes and enhancing capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitor electrodes are formed in deep openings to increase vertical dimension and capacitance, then storage capacitance is improved, but the electrodes become prone to toppling during etching and processing
Solution Approach 1:
The method performs preliminary actions by forming a sacrificial layer and patterned masking structure before etching the deep openings. This preliminary structuring provides support during the etching process and prevents electrode toppling, while still allowing the formation of tall electrodes for increased capacitance.
Solution Approach 2:
The patent introduces intermediate structures including a sacrificial layer and patterned masking material that act as mediators during the etching process. These intermediate elements provide mechanical support to the tall electrodes during processing, preventing toppling while allowing the electrodes to maintain their increased vertical dimension for higher capacitance.
2Reliability
If outer sidewall surfaces of electrodes are exposed to increase capacitance area, then storage capacitance is improved, but the tall and narrow electrodes become unstable and topple
Solution Approach 1:
The etching process is segmented into multiple stages with different masking patterns. The patterned masking structure is formed in segments that allow controlled exposure of outer sidewall surfaces while maintaining support for the electrodes. This segmented approach enables the formation of increased capacitance area without causing electrode toppling.
Solution Approach 2:
The patterned masking structure is formed preliminarily before the final etching step that exposes outer sidewall surfaces. This preliminary masking provides structural support during critical processing steps, enabling subsequent exposure of sidewalls for increased capacitance without causing electrode instability.
3Productivity
If capacitor area is decreased to increase integrated circuit density, then device density is improved, but storage capacitance becomes difficult to maintain
Solution Approach 1:
The patent transitions from horizontal capacitor expansion to vertical capacitor growth by forming deep openings and tall electrodes. This dimensional change allows capacitance to be maintained or increased while the horizontal footprint is reduced, thereby increasing integrated circuit density.
Solution Approach 2:
The method performs preliminary formation of support structures and patterned masking before creating the deep vertical openings. This preliminary structuring enables the subsequent formation of tall, narrow electrodes that provide high capacitance in a reduced horizontal area, achieving both high density and maintained capacitance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively stabilizes capacitor electrodes and increases capacitance by exposing and removing support material, preventing toppling and ensuring efficient formation of capacitors with improved storage capacity.
Implementation Method 1
A first etching is conducted only partially into the support material using a liquid etching fluid to expose an elevationally outer portion of sidewalls of individual of the first capacitor electrodes
Implementation Method 2
A second etching is conducted into the support material using a dry etching fluid to expose an elevationally inner portion of the sidewalls of the individual first capacitor electrodes
Data Source
AI summary
A method of forming capacitors includes forming support material over a substrate. A first capacitor electrode is formed within individual openings in the support material. A first etching is conducted only partially into the support material using a liquid etching fluid to expose an elevationally outer portion of sidewalls of individual of the first capacitor electrodes. A second etching is conducted into the support material using a dry etching fluid to expose an elevationally inner portion of the sidewalls of the individual first capacitor electrodes. A capacitor dielectric is formed over the outer and inner portions of the sidewalls of the first capacitor electrodes. A second capacitor electrode is formed over the capacitor dielectric.